From 33a63bb8d9e56424140d4b546bad5d10a3da97aa Mon Sep 17 00:00:00 2001
From: Bruce Hill <bruce@bruce-hill.com>
Date: Fri, 30 Jul 2021 14:54:28 -0700
Subject: Improved error checking

---
 bp.c    |  2 +-
 files.c |  4 ++--
 utils.c | 14 ++++++++++----
 utils.h | 11 ++++++++---
 4 files changed, 21 insertions(+), 10 deletions(-)

diff --git a/bp.c b/bp.c
index 64990a6..64db5e4 100644
--- a/bp.c
+++ b/bp.c
@@ -458,7 +458,7 @@ static int process_git_files(def_t *defs, pat_t *pattern, int argc, char *argv[]
     if (child == -1)
         err(EXIT_FAILURE, "Failed to fork");
     if (child == 0) {
-        const char **git_args = memcheck(calloc((size_t)(2+argc+1), sizeof(char*)));
+        const char **git_args = new(char*[2+argc+1]);
         int g = 0;
         git_args[g++] = "git";
         git_args[g++] = "ls-files";
diff --git a/files.c b/files.c
index fc60171..202c88d 100644
--- a/files.c
+++ b/files.c
@@ -88,7 +88,7 @@ file_t *load_file(file_t **files, const char *filename)
     }
     size_t length;
     file_t *f = new(file_t);
-    f->filename = memcheck(strdup(filename));
+    f->filename = checked_strdup(filename);
 
     struct stat sb;
     if (fstat(fd, &sb) == -1)
@@ -150,7 +150,7 @@ file_t *spoof_file(file_t **files, const char *filename, const char *text, ssize
     if (filename == NULL) filename = "";
     file_t *f = new(file_t);
     size_t len = _len == -1 ? strlen(text) : (size_t)_len;
-    f->filename = memcheck(strdup(filename));
+    f->filename = checked_strdup(filename);
     f->memory = new(char[len+1]);
     memcpy(f->memory, text, len);
     f->start = &f->memory[0];
diff --git a/utils.c b/utils.c
index 3a950c8..578b59c 100644
--- a/utils.c
+++ b/utils.c
@@ -4,6 +4,7 @@
 
 #include <ctype.h>
 #include <err.h>
+#include <stdarg.h>
 #include <stdlib.h>
 #include <unistd.h>
 
@@ -124,12 +125,17 @@ char unescapechar(const char *escaped, const char **end)
 }
 
 //
-// Fail and exit if a memory value is NULL
+// If the given argument is NULL, print the error message and exit with
+// failure. Otherwise return the given argument.
 //
-void *memcheck(void *p)
+void *check_nonnull(void *p, const char *err_msg, ...)
 {
-    if (p == NULL)
-        err(EXIT_FAILURE, "memory allocation failure");
+    if (p == NULL) {
+        va_list args;
+        va_start(args, err_msg);
+        verr(EXIT_FAILURE, err_msg, args);
+        va_end(args);
+    }
     return p;
 }
 
diff --git a/utils.h b/utils.h
index 08830be..c029ca5 100644
--- a/utils.h
+++ b/utils.h
@@ -12,9 +12,14 @@
 
 #include "match.h"
 
+#define S1(x) #x
+#define S2(x) S1(x)
+#define __LOCATION__ __FILE__ ":" S2(__LINE__)
+
 #define streq(a, b) (strcmp(a, b) == 0)
-#define new(t) memcheck(calloc(1, sizeof(t)))
-#define grow(arr,n) memcheck(realloc(arr,sizeof(arr[0])*(n)))
+#define new(t) check_nonnull(calloc(1, sizeof(t)), __LOCATION__ ": `new(" #t ")` allocation failure")
+#define checked_strdup(s) check_nonnull(strdup(s), __LOCATION__ ": `checked_strdup(" #s ")` allocation failure")
+#define grow(arr,n) check_nonnull(realloc(arr,sizeof(arr[0])*(n)), __LOCATION__ ": `groaw(" #arr ", " #n ")` allocation failure")
 
 __attribute__((nonnull(1)))
 char unescapechar(const char *escaped, const char **end);
@@ -27,7 +32,7 @@ bool matchchar(const char **str, char c);
 __attribute__((nonnull))
 bool matchstr(const char **str, const char *target);
 __attribute__((returns_nonnull))
-void *memcheck(/*@null@*/ /*@out@*/ void *p);
+void *check_nonnull(void *p, const char *err_msg, ...);
 __attribute__((nonnull))
 int memicmp(const void *s1, const void *s2, size_t n);
 __attribute__((nonnull))
-- 
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